Traditional disk

In a traditional PC-style embedded system with a BIOS, this
is the simplest boot possible. The BIOS performs all the
work for you — it fetches the image from disk,
transfers it to RAM, and starts it.

On the other hand, if you don't have a BIOS but you wish to
implement this kind of a boot, then this method involves the
most complicated processing discussed so far. This is
because you'll need a driver that knows how to access the
disk (whether it's a traditional rotating-medium hard disk
or a solid-state disk). Your IPL code then needs to look
into the partition table of the device and figure out where
the contents of the image reside. Once that
determination has been made, the IPL then needs to either
map the image portions into a window and transfer bytes to
RAM (in the case of a solid-state disk) or fetch the data
bytes from the disk hardware.